Nowadays, the term “dual-SIM dual-standby” means that two SIM cards may be inserted into a mobile phone or other terminals, and can be standby simultaneously.
For example, a consumer may use telephone numbers for two Global System for Mobile Communication (GSM) networks simultaneously on a single GSM dual-SIM dual-standby mobile phone, and may use telephone numbers for two Code Division Multiple Access (CDMA) networks simultaneously on a single CDMA dual-card dual-standby mobile phone.
In general, dual-SIM dual-standby may be set to be one of the following cases.
1. Only a SIM card 1 is active.
2. Only a SIM card 2 is active.
3. Both cards are active.
It may be understood that dual-SIM dual-standby enables the demand for communication of a user to be better met, and meanwhile, the communication cost is reduced.
From the perspective of technical implementation, there are several dual-SIM solutions on the market. One solution uses two sets of chips, i.e., two sets are installed in a mobile phone, each comprising a baseband chip, a radio frequency chip and a memory system, and two complete phone motherboards are combined and arranged in the same housing of the mobile phone. Another solution adds an analog switch to a traditional chipset of a mobile phone for manually switching networks. Yet another solution uses a software to manage a control Integrated Circuit (IC) chip to continuously switch between two networks for automatically searching for networks.
However, when an incoming call or a short message via different cards is replied, the mobile phone or other terminals using the above-mentioned solutions cannot match the reply to the incoming call or the message corresponding to a different card to a corresponding SIM card. For example, when an opposite party sends a short message to the SIM card 2 and the SIM card 1 of the mobile phone is set as a primary SIM card, the SIM card 1 may be unknown to the opposite party during the reply, and in order to switch to a number capable of being identified by the opposite party, the user needs to manually switch.